I get it

"Could you try not aiming so much? […] If you hit him when you aim, it'll just be luck. […] You'll be glad if you hit his marble - Ira's marble - won't you? Won't you be glad? And if you're glad when you hit somebody's marble, then you sort of secretly didn't expect too much to do it. So there'd have to be some luck in it, there'd have to be slightly quite a lot of accident in it." ("Seymour" 8.9)